I. Field of the Invention
This invention relates to a method for preparing symmetrical azines as well as mixtures containing symmetrical and unsymmetrical azines.
II. Description of the Prior Art
Aldehydes are known to react with ammonia in a complex manner giving rise to various addition, condensation or polymerization products (see for example, The Chemistry of the Carbon-Nitrogen Bond, S. Patai, Interscience, London, 1967, page 67) which can react with hydrogen peroxide to form unstable peroxide products.
Moreover, it is known that ammonia, an aldehyde or ketone, and hydrogen peroxide react together to produce aminoperoxides (J. Chem. Soc. 1969, C, page 2663) and in the presence of such catalysts as tungstic or molybdic acid, a mixture of cyclohexanone and ammonia is oxidized by hydrogen peroxide to form cyclohexanoneoxime (J. Gen. Chem. (U.S.S.R.) 1960, 30, 1635), or in the presence of the ammonium salts or hydroxides of metals of Group Ia and IIa of the Periodic Table of the Elements, result in azines (see copending application Ser. No. 267,921 filed June 30, 1972, now abandoned.
Another method for preparing azines comprises the oxidation of ammonia in the presence of a ketone or aldehyde by means of an oxidizing medium comprising hydrogen peroxide and cyanogen or a nitrile. This method is fully disclosed in commonly assigned pending U.S. application Ser. No. 152,413, filed June 11, 1971, now abandoned.
Still another method for preparing azines comprises oxidizing a secondary alcohol in the liquid phase to form peroxide products of the auto-oxidation of the alcohol and subsequently reacting the peroxidic products with ammonia in the presence of cyanogen or a nitrile. This method is fully disclosed in commonly assigned pending U.S. application Ser. No. 230,038, filed Feb. 28, 1972, now abandoned.
Percarboxylic acids are also known to react with N-substituted imines in an anhydrous medium to give oxaziridines (German patents 952,895 and 959,094).